1. Field of the Invention
The present invention relates to a testing system for a display device. More specifically, the present invention relates to a system and method for testing and evaluating a display device and its associated display drive circuitry through computer generated graphic test patterns which are dynamically alterable.
2. Background Art Related to the Invention
Over the last decade, a variety of conventional systems have been developed to generate graphic test patterns, namely particularly chosen computer-generated objects (e.g., vertical or horizontal bars, stationary squares, etc.) onto a two-dimensional, phosphor coated, raster scanned display screen such as a cathode ray tube ("CRT") display. Since the CRT is a "temporal" display usually experiencing time-related video artifacts defined as abnormal video performance (e.g., geometric distortions, illuminance variations and pixel instability), these conventional systems generate a variety of static (i.e. spatially fixed), graphic test patterns and then transmit these test patterns to the CRT. Although these conventional systems may be effective for detecting certain video artifacts, they are not effective for testing flat panel displays e.g., liquid crystal displays (LCDs) such as thin film transistor LCDs ("TFT LCDs") and Super Twist Nomadic LCDs ("STN LCDs").
A primary reason for such ineffectiveness is that the conventional testing process utilizes static test patterns which are incapable of being dynamically altered by a test operator based on his or her subjective observations or objective observations by testing equipment. For example, it is being discovered that although flat panel display devices may appear to be devoid of any video artifacts based on conventional non-alterable test patterns, slight changes to these test patterns uncover many video artifacts that never would have been detected by conventional test systems.
Another disadvantage evident in testing of flat panel displays is that these displays are configured to support a predetermined pixel geometry (pixel size, number of pixels, size of scan lines, etc.) and a particular manner driving the pixels. Since configurations of flat panel displays vary considerably between different manufacturers and different product lines from one manufacturer, the testing of these flat panel displays using test patterns of conventional pattern generation systems is highly unreliable.
Yet another disadvantage associated with using static test patterns for flat panel displays is that only a limited number of graphic test patterns are available to the test operator. As a result, the test operator typically is unable to localize the test pattern about a certain location of the display to further study a potential error. To do so, he or she would be required to write a new software program which is time-consuming and cost inefficient because the location may vary for different displays as discussed above.
An additional disadvantage associated with the conventional testing process is that even if a defect is detected and correct, there exists a possibility that a worst case event still exists in which the defect may reoccur if certain conditions arise. Unfortunately, the conventional system does not provide an availability of slightly altering the test patterns for detecting the worst case event.
Another disadvantage is that it is difficult to analyze display driving circuitry since video signals are complicated wave forms which are difficult to synchronize by testing equipment such as an oscilloscope.
Hence, it would be desirable to develop a system and method for testing displays and its drive circuitry, especially flat panel displays, which allow the test operator to dynamically alter video test patterns so that further measurements can be performed based on subjective or objective observations. The present invention, in fact, provides for such testing as described in the following sections.